I have a L185 so it is a different tractor than what you have. Not sure what you have for the ROPS but mine looks kind of like a large light bulb. On mine the ROPS is made in two pieces. It was difficult to get on so I did it one side at a time and then got the top aligned and bolted together. The bracket that attaches the top link to the tractor is bolted on the back side of the ROPS so you may need some new bolts. Saying that another way, there are tapped holes in the back of the tractor case. The top two bolts are replaced with long studs that go through the ROPS and the bracket. Then 4 additional long bolts go through the bracket and ROPS into the tractor. You will probably have to get shorter high strength (10.9 in metric world) to use.
Try to find out the torque values for the bolts holding on the ROPS.
It is not too difficult to take mine off and on but I don't want to do it often.
It requires some help or an overhead lifting point (tree, beam..) to get it done by yourself. I would guess about one hour to get it off, about two to get it back on.